Description SUMMER ADULT Often looks mainly dark, but plumage's oily sheen and black-bordered brownish wing feathers are seen in good light. Eye is green and skin at base of bill is yellow, grading to white. In full breeding plumage, has white thigh patch and white on head and neck. WINTER ADULT Loses white feathering. JUVENILE Has brown upperparts and whitish underparts; acquires adult plumage over next 2 years.

Dimensions Length: 35-40" (89-102 cm)

Habitat Nests colonially on undisturbed rocky coasts from Newfoundland to Maine. Present in nearby coastal seas year-round, but many birds move south down Atlantic seaboard in winter.

Discussion Large, dark waterbird with a heavy, hook-tipped bill. Found mainly in coastal waters. Swims low in water and dives (typically with a noticeable leap) for fish, propelling itself with large webbed feet. Flies with head and neck held forward and often perches on rocks or posts with wings outstretched to dry. Sexes are similar.